Japanese Patent Application Publication No. 2006-77631 (JP2006-77631A) discloses a centrifugal fan referred to as a sirocco fan. The fan comprises an impeller and a casing. The impeller comprises a plurality of blades. The impeller is fixed to the rotary shaft of an electric motor to rotate therewith. The casing includes a suction port and a discharge port. The suction port opens in an axial direction of the rotary shaft, and the discharge port opens in a direction tangent to a direction of rotation of the impeller. The casing includes a first wall portion in which the suction port is formed, a second wall portion facing the first wall portion, and a third wall portion including the discharge port. The third wall portion couples the first and second wall portions. The impeller includes an impeller body and a blade support body. The impeller body has a cylindrical circumferential wall which rotates about the rotary shaft. The blade support body is fixed to an end of the impeller body to support the blades and extends in a radial direction. The blade support body is shaped like a circular plate having an opening in its center. The periphery of the opening of the blade support body is fixed to the circumferential wall of the impeller body. The blades are fixed to a radially outside end portion of the blade support body. The blades extend from the radially outside end portion of the blade support body toward the first wall portion of the casing. End portions of the blades on the side of the first wall portion are fixed to an annular blade mounting member which is disposed concentrically with the circumferential wall of the impeller body.
A centrifugal fan disclosed in Japanese Patent Application Publication No. 2004-353665 (JP2004-353665A) includes an annular blade mounting member which is located closer to a suction port side than a blade support body and to which a plurality of blades are fixed. The blades extend beyond the annular blade mounting member toward a first wall portion in which a suction port of a casing is formed. End portions of the blades on aside of the suction port are located in the vicinity of the suction port of the casing.